Exam 3- BIO 201 Sniegowski ASU
Downtown-Questions All Answered
Correctly 2026 Updated.
Skeletal muscles are served by "______________". - Answer Somatic motor neurons.
Somatic motor neurons - Answer Nerve cells whose cell bodies are in the brainstem and spinal
cord that serve skeletal muscles
The "______________" lead to the skeletal muscles. - Answer Somatic motor fibers.
Each muscle fiber is supplied by only "________" motor neuron - Answer one
Each nerve fiber branches out to a number of "________________". - Answer Muscle fibers
Motor unit - Answer one nerve fiber and all the muscle fibers innervated by it; they behave as
a functional unit
Muscle fibers of one motor unit: - Answer Are dispersed throughout the muscle
• Contract in unison
• Produce weak contraction over a wide area
• Provide the ability to sustain long-term contraction as motor units take turns contracting
Effective "______________" usually requires contraction of several motor units at once -
Answer Contraction
The average motor unit contains "________" muscle fibers distributed across as many as
"_______" fascicles - Answer 200; 100.
"_______________" provide a fine degree of control. - Answer Small motor units
"______________" provide more strength than control - Answer Large motor units
Large motor units provide: - Answer Powerful contractions supplied by large motor units with
hundreds of fibers
, Synapse - Answer point where a nerve fiber meets its target cell
When target cell is a muscle fiber, the synapse is also called a neuromuscular junction (NMJ) or
"____________". - Answer Motor end plate
Axon terminal - Answer swollen end of nerve fiber.
-Contains synaptic vesicles with a neurotransmitter called acetylcholine (ACh)
• Nerve impulse causes synaptic vesicles to undergo exocytosis releasing ACh into the synaptic
cleft
Synaptic cleft - Answer narrow gap between axon terminal and sarcolemma
Muscle cell sarcolemma contains millions of "____________". - Answer ACh receptors.
postsynaptic membrane: - Answer folds (junctional folds) of sarcolemma increase surface
area, maximize the number of ACh receptors• Lack of receptors causes weakness in the disease
myasthenia gravis
Entire NMJ is enclosed in the "___________". - Answer Basal lamina.
Basal lamina - Answer thin layer of collagen and glycoprotein separating muscle fiber and
nerve ending from surrounding connective tissue
acetylcholinesterase (AChE) - Answer enzyme that breaks down ACh, allowing for relaxation
Sarcolemma and lamina with synaptic cleft contain "_____________". - Answer
acetylcholinesterase (AChE)
Muscle fibers and nerve cells are "____________" cells - Answer Electrically excitable
The membranes of "__________' and "_________" exhibit voltage changes in response to
stimulation - Answer Muscle fibers; nerve cells
Electrical activity depends on concentration differences in ions in the "_________________" vs
"___________________". - Answer Intracellular fluid (ICF); extracellular fluid (ECF)
"__________" contains a greater concentration of negative anions (negatively charged proteins,
nucleic acids, phosphates) than "__________"; trapped within cell - Answer ICF; ECF
Downtown-Questions All Answered
Correctly 2026 Updated.
Skeletal muscles are served by "______________". - Answer Somatic motor neurons.
Somatic motor neurons - Answer Nerve cells whose cell bodies are in the brainstem and spinal
cord that serve skeletal muscles
The "______________" lead to the skeletal muscles. - Answer Somatic motor fibers.
Each muscle fiber is supplied by only "________" motor neuron - Answer one
Each nerve fiber branches out to a number of "________________". - Answer Muscle fibers
Motor unit - Answer one nerve fiber and all the muscle fibers innervated by it; they behave as
a functional unit
Muscle fibers of one motor unit: - Answer Are dispersed throughout the muscle
• Contract in unison
• Produce weak contraction over a wide area
• Provide the ability to sustain long-term contraction as motor units take turns contracting
Effective "______________" usually requires contraction of several motor units at once -
Answer Contraction
The average motor unit contains "________" muscle fibers distributed across as many as
"_______" fascicles - Answer 200; 100.
"_______________" provide a fine degree of control. - Answer Small motor units
"______________" provide more strength than control - Answer Large motor units
Large motor units provide: - Answer Powerful contractions supplied by large motor units with
hundreds of fibers
, Synapse - Answer point where a nerve fiber meets its target cell
When target cell is a muscle fiber, the synapse is also called a neuromuscular junction (NMJ) or
"____________". - Answer Motor end plate
Axon terminal - Answer swollen end of nerve fiber.
-Contains synaptic vesicles with a neurotransmitter called acetylcholine (ACh)
• Nerve impulse causes synaptic vesicles to undergo exocytosis releasing ACh into the synaptic
cleft
Synaptic cleft - Answer narrow gap between axon terminal and sarcolemma
Muscle cell sarcolemma contains millions of "____________". - Answer ACh receptors.
postsynaptic membrane: - Answer folds (junctional folds) of sarcolemma increase surface
area, maximize the number of ACh receptors• Lack of receptors causes weakness in the disease
myasthenia gravis
Entire NMJ is enclosed in the "___________". - Answer Basal lamina.
Basal lamina - Answer thin layer of collagen and glycoprotein separating muscle fiber and
nerve ending from surrounding connective tissue
acetylcholinesterase (AChE) - Answer enzyme that breaks down ACh, allowing for relaxation
Sarcolemma and lamina with synaptic cleft contain "_____________". - Answer
acetylcholinesterase (AChE)
Muscle fibers and nerve cells are "____________" cells - Answer Electrically excitable
The membranes of "__________' and "_________" exhibit voltage changes in response to
stimulation - Answer Muscle fibers; nerve cells
Electrical activity depends on concentration differences in ions in the "_________________" vs
"___________________". - Answer Intracellular fluid (ICF); extracellular fluid (ECF)
"__________" contains a greater concentration of negative anions (negatively charged proteins,
nucleic acids, phosphates) than "__________"; trapped within cell - Answer ICF; ECF
